1. Field of the Invention
The present invention relates generally to digital computing apparatus. More specifically, the present invention relates to network processors for processing network data elements.
2. Discussion of the Related Art
Network switches and routers, or network switch elements, form the backbone of digital networks, such as the Internet. Network switch elements connect network segments by receiving network data from ingress network segments and transferring the network data to egress network segments. Because large telecommunications switching facilities and central offices aggregate network traffic from extensive networks and many network segments, they require high-speed and high-availability switches and routers.
Network switch elements select the egress network segment by processing the address or destination included in the network data according to network data processing program logic. Traditionally, network switch elements included Application Specific Integrated Circuits (ASICs) that provided the program logic. Because ASICs are “hard-coded” with program logic for handling network traffic, they provide the high speed necessary to process a large volume of network data. ASICs, however, make it difficult to upgrade or reconfigure a network switch element, and it is expensive to design and fabricate a new ASIC for each new type of network switch element.
In response to these drawbacks, manufacturers of network switch elements are turning to programmable network processors to enable network switch elements to process network data. Programmable network processors process network data according to program instructions, or software, stored in a memory. The software allows manufacturers and users to define the functionality of the network switch elements—functionality that can be altered and changed as needed. With programmable network processors, manufacturers and users can change the software to respond to new services quickly, without costly system upgrades, as well as implement new designs quickly.
To the extent that there is a drawback to the use of programmable network processors in network switch elements, that drawback relates to speed. Because programmable network processors process network data using software, they are usually slower than a comparable hard-coded ASIC. One of the major design challenges, therefore, is developing programmable network processors fast enough to process the large volume of network data at large telecommunications switching facilities.
One technique used to increase speed in traditional processor design is “parallel processing,” or processing multiple instructions in parallel. Parallel processing requires that instructions processed in parallel share access to devices, such as memory or peripherals. Known systems and methods for sharing access to devices, however, are not suitable for use in programmable network processors because network data is received at very high speeds, and must be processed on a time critical basis. Traditional device access techniques introduce unacceptable delays and timing problems into the network data processing.